Single rotary valve for hydraulic fluid and air



Oct. i5, i968 1. E. CLARKE 3,405,601

SINGLE ROTARY VALVE FOR HYDRAULIC FLUID AND AIR Filed March 23, 1966 (gli Vl.

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Y' @55e al' e l; Z BY yg www, @OMIM United States Patent O 3,405,601 SINGLE ROTARY VALVE FOR HYDRAULIC FLUID AND AIR Jesse E. Clarke, Hinsdale, lll., assigner to Autoquip Corporation, Chicago, Ill., a corporation of Illinois Filed Mar. 23, 1966, Ser. No. 536,788 7 Claims. (Cl. 91-4) ABSTRACT OF THE DISCLOSURE A unit-ary two-part control valve is provided for an air-hydraulic system for operating a hydraulic cylinder. The valve comprises a cylindrical valve rotor in a valve body. The valve rotor is biased .to an intermediate position and is movable 90 degrees in either direction from the intermediate position to two end positions respectively. At one position along the axis of the rotor there is a hydraulic fluid passage diametrically therethrough. At the same longitudinal position the valve body has diametrically opposed ports, one port being adapted to be connected to the hydraulic cylinder and the other port adapted to be connected to the hydraulic reservoir below the level of the hydraulic fluid therein. At one end of the rotor an air passage extends from the end of the rotor into the interior of the rotor and then radially through the side of the rotor at a second position along the longitudinal axis thereof. At said second position the valve body has two diametrically opposed ports, one being the exhaust port and the second being adapted to be connected to the source of compressed air. At said end of the rotor, the valve body has an air port adapted to be connected to the hydraulic reservoir above the level of the liquid therein. Extending from the radial end of the air passage in the rotor is a small bleed passage about the periphery of the rotor which, when the rotor is in the intermediate position, communicates with the exhaust port. With the rotor in the intermediate position'the communication between the cylinder port and reservoir hydraulic port is shut off as is communication between the compressed air port and the air passage in the rotor. When the rotor is moved to one end position the cylinder and the hydraulic reservoir ports are in communication and the -air passage of the rotor is in communication with the compressed air port. At the other end position of the rotor the cylinder and the hydraulic reservoir ports are in communication and the air passage of the rotor communicates with the exhaust port.

Background of the invention One well-known form of hydraulic elevating device uses a single hand-operated valve for controlling the ow of compressed air into and out of a hydraulic uid reservoir. Movement of the valve to one position permits compressed air to enter and pressurize the hydraulic fluid within the reservoir. The pressurized liuid then flows through an open line to a hydraulic cylinder and raises a platform or the like. To lower the platform the hand operated valve is pivoted to a different position which opens the reservoir to the atmosphere and permits the compressed air therein to exhaust. The platform then lowers accordingly. This type of system is frequently used in automotive garages because of its simplicity and because these garages normally already have a source of compressed air for performing other services such .as intlating tires, greasing, etc. A distinct disadvantage of such a system results from the compressible nature of air which gives the lift a genice erally spongy characteristic making it ditiicult to accurately position and lock the lift at a height intermediate of its end positions.

Where more accurate control of the vertical positioning lift is required, a second control valve is frequently interposed in the hydraulic uid line which extends between the reservoir and the hydraulic cylinder. After pressurizing Ithe reservoir by means of the first or compressed air valve, the second valve is opened to control the flow of uid into the hydraulic cylinder, thus substantially eliminating the spongy effect of the compressed air. Of course, if the lift operator overshoots the desired platform height, he must depressurize the reservoir with the lirst valve in order to permit drainage from the cylinder to the reservoir by means of the second valve. For this reason, many experienced lift operators save time in accurately controlling the vertical positioning of the platform by endeavoring to simultaneously manipulate both valves, each with a different hand. Until the lift operator is thoroughly experienced in the use of this two-valve system, he is likely to waste time adjusting the platform to the desired height, and more importantly, the confusion resulting from the novices attempt to use two handles simultaneously could cause injury to objects or people in the path of movement of the platform.

It is therefore a general object of this invention to provide a single control for a pneumatically powered hydraulic lift system which both controls the flow of compressed air into and out of the hydraulic iiuid reservoir as well as accurately metering the ow of hydraulic fluid into or out of the lift cylinder.

An advantage and feature of the invention resides in the provision of means by which the reservoir is inherently depressurized after being elevated, thereby eliminating the task of depressurizing the reservoir before lowering the platform.

Other objects, advantages `and features will become apparent upon a reading of the following description when taken in conjunction with the following drawings, wherein:

FIGURE 1 is a schematic diagram of a sample form of hydraulic elevating system including a separated land broken away View of the valve assembly which incorporates the principles of one preferred form of the present invention;

FIGURE 2 is a cross-sectional view of the valve assembly shown in FIGURE 1; and

FIGURE 3 is a cross-sectional view of the valve assembly shown in FIGURES 1 `and 2 taken substantailly along the lines 3 3 of FIGURE 2.

Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

Referring now to the drawings in more detail, control valve assembly generally 10 forms a portion of a hydraulic lift system which also includes a hydraulic fluid reservoir 11 `and a hydraulic cylinder 12. Reservoir 11 has an air connection 11a above the liquid level and a liquid connection 11b below the liquid level. cylinder 12 may be conventionally connected to a vertically movable platform or the like for raising a load. A source of compressed air, as at 13, is used to power the lift system, this source taking any conventional and convenient form.

Control valve assembly includes a main valve body 14 having an elongate cylindrical portion 15 defining a first end 16 and a second end 17. Elongate cylindrical portion consists essentially of an outer shell or casing 18 having an outer surface 19 and an inner surface 20, and a bearing 21 carried therein and bonded to the inner surface of outer casing 18. Bearing 21 has an elongate cylindrical hole 22 extending axially therein from the rst end 16. Extending between cylindrical hole 22 and the second end 17 of the valve body is an air passagevor port 23 threaded internally to adapt it for connection with the air connection 11a of the hydraulic fluid reservoir 11.

Extending transversely through cylindrical portion 15 is a first pair of axially aligned and diametrically opposed ports or holes 25 and 26 forming two separated portions of a hydraulic luid passage. Hole 25 communicates with fluid connection 11b of reservoir 11 by means of an internally threaded connector 27 welded to and forming another portion of the main valve body 14. Similarly, hole 26 is adapted for fluid communication with cylinder 12 by meansof an internally threaded connector 30, also welded to the outer surface 19 of main valve body 14 and forming a portion thereof.

Longitudinally spaced from holes 25 and 26 are a second pair of axially aligned and diametrically opposed ports or holes 31 and 32 extending through the side walls of main valve body 14. Holes 31 and 32 are not only spaced from holes 25 and 26 longitudinally along cylindrical portion 15, but are also rotated 90 degrees relative thereto. Alhough the valve assembly 10 could be designed to work equally well regardless of the angle between the first and second pair of holes, it will be understood that the alignment shown permits the longitudinal distance therebetween to be held to a minimum, thereby minimizing the length of cylindrical portion 15, Also, this 90 degree offset separates the connections to facilitate the attachment of various fluid lines into the main valve body. Hole 31 comprises one portion of a compressed air inlet passage and hole 32 comprises one portion of an air exhaust passage.

Welded to the outside surface 19 of main valve body 14, so as to form an integral part thereof, is a laterally extending portion 34 having an elongate guide hole 35 extending therethrough of the same diameter as air inlet hole 31 and in axial alignment therewith. The outermost end of guide hole 35 is threaded as at 36 to receive a spring preload adjusting screw 37 which is threaded over its entire length, a portion of which projects outwardly beyond the outermost end of extension 34. Screw 37 is locked in place by means of a nut 38 drawn up thereon, and air leakage between screw 37 and threads 36 is prevented by means of a sealing washer 39. Compressed air gains entry into the central portions of guide hole 35 by way of a transverse passage 40. Passage 40 is threaded to facilitate connection with compressed air source 13.

Slideably carried within axially aligned holes 31 and 35 is an elongate and cylindrical sealing member 41 having a central hole 42 extending longitudinally therethrough. Sealing member 41 is preferably constructed of a resilient material such as rubber tubing. A compression spring 43 is interposed in guide hole 35 between adjusting screw 37 and sealing member 41 to bias sealing member 41 towards cylindrical hole 22 in the main valve body 14. Also welded to the outer surface 19 of main valve body 14, and in `axial alignment with exhaust hole 32, is an internally threaded connector forming a part of the main valve body 14 and adapting exhaust hole 32 for connection with an air exhaust line. Obviously, main valve body 14 could be fabricated in other ways, as by casting, and less expensive forms might eliminate the use of bearing 19 as a separate element.

Pivotally carried within cylindrical hole 22 of the main valve body 14 are means for selectively permitting and restraining fluid flow through the control valve assembly 10. Herein these means comprise movable closure means in the form of a valve rotor 54 having an elongate and generally cylindrical portion 55 extending into cylindrical hole 22 from the first end 16 of the main valve body. Innermost end 56 of the valve rotor lies adjacent the second end 17 of the main valve body. The diameter of cylindrical portion 55 is slightly less than the diameter of cylindrical hole 22 to permit relative rotation but prevent iluid leakage therebetween. Valve rotor 54 also has an increased diameter portion 57 lying adjacent the outer end of bearing 21 and forming an inwardly facing shoulder 58 and an outwardly facing shoulder 60. A reduced diameter portion 61 of rotor 54 extends further outwardly from the first end 16 of the main valve body 14.

Cylindrical portion 55 is restrained from appreciable axial movement relative to the main valve body. Herein these restraining means include a washer 62 resting against outwardly Afacing shoulder `60 and held in place by means of a C-ring 63 snapped in place within an internal annular groove provided therefor in the casing 18, thus preventing withdrawal of the valve rotor. Shoulder 58 rests on the iirst end portions of bearing 21 thereby preventing further entry of the valve rotor 54 into the cylindrical hole 22.

Extending transversely through cylindrical portion 55 of the valve rotor is a hydraulic fluid passage 66 positioned longitudinally relative to valve body cylindrical portion 15 between holes 25 and 26 therein. When valve rotor 54 is pivoted such that passage 66 is aligned with holes 25 and 26, hydraulic fluid can flow therebetween; and vwhen passage 66 is pivoted out of alignment with these holes, hydraulic iluid flow is prevented.

Longitudinally spaced from passage 66 is an internal air conducting passage 67. One end 68 of air conducting passage 67 opens outwardly at the innermost end 56 of cylindrical portion 55 Where it is in fluid communication with air passage 23 in the main body. The other end 69 of passage 67 opens outwardly through the side wall of rotor cylindrical portion 55 at a longitudinal position on the valve body corresponding to the longitudinal posion of holes 31 and 32 in the main valve body. Side opening 69 of air conducting passage 67 is -generally 90 degrees displaced from each of the side openings of the hydraulic fluid passage 66. It can thus be seen that selective pivoting of the rvalve rotor permits iluid (air) communication between passage 23 and hole 31 or between passage 23 and hole 32, or alternatively, prevents fluid communication when side opening 69 is not aligned with either of the holes 31 and 32.

Three O-ring seals 70 are mounted on rotor cylindrical portion 55 to prevent the escape of ud out of the valve body or between the air conducting passages and hydraulic fluid conducting passage. One is positioned between shoulder 58 and passage 66; another is positioned between passa-ges 66 and 67; and the third is positioned between side opening 69 and innermost end 56 of valve rotor 54.

Means are provided for permitting selective pivotal movement of the valve rotor, and herein these means include a member 71 having end portion 72 mounted over reduced diameter portion 61 of the valve rotor and rigidly aiiixed thereto by means of a pin 73. The other end 75 of member 71 carries a handle 76 pinned thereto as at 77. Member 71 also includes a transversely protruding arm 78 having a pair of holes 80 therein in which are mounted a pair of tension springs 81 for biasing the valve rotor 54 to the angular position shown in FIGURES 1 and 2, thereby normally maintaining the fluid passages in a closed condition.

Reservoir pressure relief means are also provided, and herein these means comprise a small bleed passage in the form of a surface indentation or scratch 82 extending peripherally around rotor 54 generally 90 degrees between the side opening 69 of air conducting passage 67 to a position exposed to hole 32 when the valve rotor is in its biased closed position. This indentation is relatively small to permit a relatively slow depressurization of the reservoir, the reasoning for which will be discussed 1n greater detail later.

In operation, and assuming the valve rotor 54 is biased closed, hole 35 is at a high pressure Ibecause it is connected by way of an open line to the compressed air source 13. This pressure is exerted through central hole 42 in the sealing member 41, but is unable to escape to exhaust hole 32 between the outer surface of cylindrical rotor portion 55 and the inner surface of bearing 21 because of an air-tight seal formed between resilient sealing member 41 and cylindrical portion 55 under the bias of compression spring 43.

When it is desired to raise the lift platform or the like, handle 76 is pivoted approximately 90 degrees in a clockwise direction (FIGURE 1) from its biased closed position to align the side opening 69 of air conductlng passage 67 with hole 42 in the sealing member 41. Generally concurrently therewith, hydraulic uid conducting passage 66 in the valve rotor becomes aligned with holes 25 and 26 in the main valve body. As compressed a1r passes through rotor passage 67 and bearing passage 23 into the hydraulic liuid reservoir, the pressure in the reservoir increases and forces hydraulic fiuid from the reservoir through passage 66 in the valve rotor and into the hydraulic cylinder 12. As the platform approaches its desired height, its rate of ascent can Ibe diminished by pivoting the handle 76 and closing down the opening formed by hydraulic fluid passage 66. When the exact height is reached the valve is manually pivoted to close off hydraulic fluid passage 66 and the platform is fixed.

In the well known systems using two separately controlled valves, it is necessary to exhaust the air pressure from the reservoir before lowering the platform in order to permit the fluid to ow Iback into the reservoir. Ho w ever, the system herein disclosed eliminates the necesslty of first exhausting this air pressure prior to lowering the lift platform. The small passage or indentation 82 permits this pressure to Ibleed ofi:` and exhaust through 82 after the lift has been elevated and the valve rotor 54 has been biased to its closed position. This bleeding off provides a safety feature to ensure that the residual pressure in the reservoir does not cause the lift platform to unexpectedly raise prior to lowering when the valve rotor is rotated in the direction permitting lowering of the platform.

Therefore, when it is desired to Ilower the platform, handle 76 is merely rotated 90 degrees in the opposite direction from that required to raise the platform. The hydraulic uid is then free to ow from the cylinder 12 through passage 66 in the valve rotor and back to the hydraulic uid rese-rvoir 11.

It can thus be seen that the control valve assembly permits single handle control of a hydraulic lift platform, and also eliminates the necessity of exhausting air pressure from the reservoir prior to lowering the platform.

I claim:

1. In a gas-liquid hydraulic system for use with a source of compressed gas and comprising a uid reservoir having a gas connection above the fiuid level therein and a liquid connection below the uid level therein, a fiuid operated cylinder normally urged to the retracted position, a valve means connected to the cylinder, the source, the gas and fluid connections and to a gas exhaust to control the flow of gas between the source, the exhaust and the reservoir and to control the ow of liquid between the reservoir and the cylinder, the improvement comprising: said valve means being a unitary two-part valve including a valve body with a valve member movable therein between three positions to wit, a first end position, an intermediate position and a second end position, one part of said valve means comprising a first portion of said member defining a first fiuid passage and a first portion of the body defining a cylinder port and a liquid connected reservoir port, said first fluid passage communicating with both ports when the member is in the first and second positions and blocking communication between the ports when the member is in the intermediate position, the second part of the valve means comprising a second portion of said member defining a second fluid passage, a second portion of the body defining a gas source port, an exhaust port and a gas connected reservoir port, said second fluid passage communicating with said source port and with said gas connected reservoir port when said member is in the first position and with said exhaust and said gas connected reservoir port when the member is in' the second position, whereby when said member is in the first position gas will be fed from said source to said reservoir and liquid will flow from the reservoir to the cylinder and when said member is in the second position gas will ow from the reservoir to exhaust and liquid will flow from the cylinder to the reservoir.

2. In a system as set forth in claim 1, wherein said second portion of said member defines a bleed passage of smaller gas transmitting capacity than said second fiuid passage, said bleed passage being in communication with said gas connected reservoir port and with the exhaust port when the member is in the intermediate position.

3. In a system as set forth in claim 2, including resilient means connected to said member to resiliently urge said member to said intermediate position.

4. In a system as set forth in claim 3, wherein said valve member is a solid of revolution about an axis, said first fluid passage extending radially through said member, said second fluid passage extending from the interior of the member to one side and from the interior of the member to the adjacent end of the member, said body defining an interior opening of substantially the same configuration as the exterior of the member to fit closely thereabout, said cylinder port and said liquid connected reservoir port being diametrically opposite each other in the body and in the same position along the axis as the ends of said first passage, said gas source port and said exhaust port being diametrically opposite each other in the body and in the same position along the axis as the side end of the second fiuid passage, said gas connected reservoir port being in the end of the body corresponding to said adjacent end of the member and in communication with the second fiuid passage at said adjacent end; and including O-ring seals between the body and the member at each side of said two passages.

5. In a system as set forth in claim 4, wherein said member is cylindrical and said bleed passage is a groove at the exterior of the member.

6. In a system as set forth in claim 1, wherein said valve member is a solid of revolution about an axis, said first fiuid passage extending radially through said member, said second iiuid passage extending from the interior of the member to one side and from the interior of the member to the adjacent end of the member, said body defining an interior opening of substantially the same configuration as the exterior of the member to fit closely thereabout, said cylinder port and said liquid connected reservoir port being diametrically opposite each other in the body and in the same position along the axis as the ends of said first passage, said gas source port and said exhaust port being diametrically opposite each other in the body and in the same position along the axis as the side end of the second fiuid passage, said gas connected reservoir port being in the end of the body corresponding to said adjacent end of the member and in communication with the second fluid passage at said adjacent end; and including O-ring seals between the body and the member at each side of said two passages.

7. In a system as set forth in claim 6, including resilient means connected to said member to resiliently urge said member to said intermediate position.

(References on following page) 7 8 References Cited 3,217,744 11/ 1965 Y Racicot 137-625.23 Howard 5/1931 Hansen 91-4 4/19'54 Aikman 91-4 5 MARTIN P. SCHWADRQN,l Plzmary Examiner.. 12/ 1955 Bonham 137-625.23 B. L. ADAMS, Assistant Examiner.

4/1965 Konkle 91-4 

